Where Are the Obesity Genes?

Edward Archer, Ph.D., studies obesity at the Nutrition and Obesity Research Center at the University of Alabama at Birmingham. His fields of expertise are many—computational physiology, psychology, nutrition, exercise science, and epidemiology. Yet, in explaining his theory of non-genetic evolution as obesity villain, Archer asked, “If our genes cause us to be fat, why has the search for ‘obesity genes‘ failed?”

It seems like obesity genes are called out on practically a daily basis. In 2008, Reuters reported the identification of six new gene mutations linked to obesity. All the variations were found to have some influence on how the brain and the nervous system control a person’s eating and metabolism. Researcher Dr. Kari Stefansson said:

This study essentially doubles in one fell swoop the number of known and replicated genetic factors contributing to obesity as a public health problem.

Then there is KSR2, which, if it suffers a mutation, can cause sluggish metabolism and increased appetite, and KLF14, which appears to be the “master switch” that controls the genes in fat tissue. This time last year, the FTO variant was making news, and no wonder. Previously it had been thought to affect one person in six. Another set of researchers said it was found in 45 percent of their study’s participants. The report says:

A common genetic mutation linked to childhood obesity also increases the likelihood of becoming overweight in adulthood.. They found the genetic variation also increases impulsive eating as well as a person’s appetite for fatty foods.

It causes higher blood levels of the “hunger hormone,” ghrelin, and increases the brain’s sensitivity to the molecule. While possession of this gene would increase a person’s likelihood of becoming obese, the study’s authors also noted that previous research showed, “exercise can still overcome the increased risk of obesity posed by the FTO variant.” Not long before that, a story about obesity prediction said:

While the researchers were unable to accurately predict child obesity risk using a formula based on genetic variations, they say about one in 10 cases of obesity are caused by rare mutations that disrupt appetite regulation.

When talking about millions and millions of obese people, one in 10 is a gigantic number. Then, there is a story about 2,500 pairs of British twins that starts by affirming that several genes that influence appetite and self-control had previously been discovered, and that size is explained “mostly by genetic factors.” Published in the journal Obesity, the twin study:

…suggests that genes account for 82 per cent of the variation in body mass index in 10-year-olds. The influence of genes on weight appeared to increase substantially throughout childhood, which scientists put down to older children having more freedom to act on their urge to eat….

According to epigenetics, the environment changes the expression of the genes. An example is a study from the Norwegian University of Science and Technology to examine how the macronutrient composition of food can affect gene expression. Dave Asprey wrote:

The group that ate a “healthy” amount of carbohydrates…expressed genes that are directly involved in some of the worst modern diseases such as type 2 diabetes, cardiovascular disease, Alzheimer’s, and cancer. The high carbohydrate group expressed a cascade of genes that trigger inflammation. Since inflammation is a contributing factor to almost every disease, it’s safe to say a high-carb diet contributes to almost every known chronic disease.

Despite all this, Dr. Archer believes that humankind will continue to be disappointed by attempts to find the genes that make us fat, because genes and food are not enough to explain the current obesity epidemic. He writes:

Despite the recent fanfare over the identification of a suite of genes associated with obesity, they explain less than 2 percent of the variation in obesity between individuals.

PROFILES: KIDS STRUGGLING WITH WEIGHT

The Book

OVERWEIGHT: What Kids Say explores the obesity problem from the often-overlooked perspective of children struggling with being overweight.

About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade. You can contact Dr. Pretlow at:

Presentations

Dr. Pretlow's 2017 Workshop on Treatment of Obesity Using the Addiction Model